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E90/E91/E92/E93 (2006 - 2013) The E9X is the 4th evolution of the BMW 3 series including a highly tuned twin turbo 335i variant pushing out 300hp and 300 ft. lbs. of torque. BMW continues to show that it sets the bar for true driving performance! -- View the E9X Wiki

Cal, notice that your top photo is of a conventional coil as used with a mechanical distributor, or very early electronic ignition. That is a two wire, dumb coil. The second photo is of a COP coil, coil on plug, like the ones we have. Notice it takes three wires. Find out why it has three wires and you are on your way to finding out where many failures occur. You must teach yourself my son.

Cal, notice that your top photo is of a conventional coil as used with a mechanical distributor, or very early electronic ignition. That is a two wire, dumb coil. The second photo is of a COP coil, coil on plug, like the ones we have. Notice it takes three wires. Find out why it has three wires and you are on your way to finding out where many failures occur. You must teach yourself my son.

2 low voltage connections for current flow through the primary coil...one high voltage to complete the circuit through the spark plug / secondary coil....

Having read codes to verify misfires, the issue is usually coil pack related, sometimes spark plug, and very rarely wires. But, how would you know what to replace? Below are DIY troubleshooting procedures. Note on spark plugs: Do NOT use anti-seize on threads! BMW plugs have surfaces that don't require this and BMW specifically recommends against. Anti-sieze results in plugs over-torqued! Big trouble - plugs broken off in head possible - best to avoid that!

50% of all my troubles were associated to the BOSCH company, whose products didn't last as expected including spark plugs and a 2 coils. I wouldn't be surprised if the 2 oxygen sensors were Bosch too but I am not sure.

50% of all my troubles were associated to the BOSCH company, whose products didn't last as expected including spark plugs and a 2 coils. I wouldn't be surprised if the 2 oxygen sensors were Bosch too but I am not sure.

I've read 35kV for N54, but that may not be accurate. Although, might be right for turbo charge, and certainly accounts for reduced plug life vs. N52, which might be 12kV. Anyone running an automotive o-scope? N55 may be exactly the same coil output.